There are several different sorts of gas canisters on the market: in the traditional walking/camping area, we have screw-thread, Campingaz, and Powermax (discontinued). In the hardware store or BBQ area, we have cheap spray-pack cans, which hold about the same amount of fuel (220 g) as a mid-sized screw-thread canister (230 g). And we also have various refill cans used for refilling cigarette lighters and so on; they usually come with a whole range of little plastic adapters in the cap. Most of the camping style canisters are expensive: close to $8 for a 230 g of butane/propane, at least here in Australia. But I can buy four of the spray cans, each holding 220 g (~400 mL) of “butane” for just $8 total at the local hardware store. That is so much cheaper!
The “butane” in these spray cans is unspecified, but it is most likely a mix of n-butane (boiling point ~32 F / 0 C) and iso-butane (boiling point 11 F / -12 C), possibly roughly in equal parts. It is doubtful whether the vendors even know what is in the cans with any accuracy. To be sure, that is not good enough for winter use in the snow, but indeed it is usable in 3-season conditions with the ambient temperature above 40 F / 5 C?
Granted, propane bought in any decent-sized container (say 5 kg and up) is even cheaper than the ~$8/kg for the butane in these cans, but just maybe the further cost savings are not nearly as significant. Added to this is the worry about putting straight propane in a canister rated only for a 30%/70% mix: if it gets warm, the canister might be approaching its burst pressure. You just don't know in advance, and if it goes bang, then it is too late.
These butane cans have a special fitting designed for little table-top stoves, sometimes called “wok stoves”. Unfortunately, the fitting is not directly compatible with our little canister stoves.
The rim around the outside of the Lindal valve and the notch in the rim is extra to what we find with our ordinary fuel canisters, but they do not get in the way. However, the metal tube up the middle above the nipple is “impossible”.
I have seen many cans advertise a thing called Rim Vent Release (RVR), which is supposed to be a safety feature. As far as I can see, the top rim has sets of three tiny slits around the rim. They are the dark marks on the rim in the left-hand photo. After examining them closely, I think these were added after the cans had been made, in a sort of retro-fit. Anyhow, if the internal pressure gets too high, first the top rim deforms, exposing lots of little leaks at those sets of slits, as shown at the left, then the overpressure is released through those leaks, as shown at the right.
You are most likely to have this problem only when running a stove with an exposed flame. So now you have a huge leak of butane next to a flame. The label on one package says “if activation occurs a controlled fire may start”.
“Controlled,” eh? Would you prefer a large ball of flame from the vents or an explosion? Hummmm: frankly, I would prefer neither.
Information on the web implies that there may also be a thermally-activated Temperature Sensing shut-off Valve (TSV) inside some butane cans, which also provides some safety. I know nothing about this, and I don't think it is globally available. It seems to me that it could lead to an explosion.
The bottom line here seems to be that no matter what you do to make something safe, there will always be a bigger fool. Be warned and take care.
Just because the standard fitting on one of these butane cans is incompatible with our stoves is not the end of the story. There are a several adapters on eBay that could allow a butane can to drive a small stove while lying sideways in its “correct” position; one of these is shown here. This correct position is how the can is mounted in a wok stove, and it has the black tab and the fuel delivery tube pointing upwards. In this position, the canister delivers a gas feed.
However, I have found the quality of most of these adapters to be poor at best: you lose a lot of liquid gas while trying to make the connection secure. It took me several goes to even make a connection the first time, and a bit of gas went squirting everywhere. I do not recommend these adapters. They might work if you practice so you can complete the connection very quickly. I would only try this outdoors.
One can also buy a different sort of adapter via eBay, which clips onto the top Lindal valve and presents a standard screw-thread connection. Typically they are either red or yellow or orange, and the body is made of aluminum. The eBay picture even shows a stove connected with one of these. These adapters generally seem to be much better made, and they are easy to attach. However, note that this only works well with a remote canister stove as the screw thread ends up pointing sideways.
If you want to use one of these adapters on a butane can to drive a small canister stove, there are some traps. For a start, the whole assembly (can, stove, pot) is quite tall and therefore rather unstable. I would have some concern that doing this with a new full butane could result in the first few minutes of operation, giving you a liquid feed rather than the gas feed you were expecting.
That is because the fuel intake inside the can has a small pipe going down a short distance, quite possibly into the liquid fuel. The photo here is from a large Chinese manufacturer of butane cans (MOQ one 20 ft container!). However, having tested this idea with a new can, I got a gas feed, so maybe the (mandatory) free space in the can is big enough, and the liquid level is below the intake.
Anyhow, if you want to use a remote canister stove lying on its side in warm weather, one of these aluminum adapters will work fine with a common and cheap butane canister. I will come to how you should lie the can down shortly.
Just one word of caution, however. These colored aluminum adapters do have a safety valve in the middle so that gas cannot escape until you attach a stove. This is good. But there have been similar adapters in black plastic rather than anodized aluminum on the eBay market in the past, and they do not have such a valve in them. You can see daylight through the middle. Attach one of those to a canister, and all the gas will come straight out, as either a liquid or a vapor, but fast. Check the hole in the middle first! Fortunately, these black plastic adapters do not seem to be available anymore.
Yes, you can use one of these black plastic adapters if you attach it to your stove first, with the stove valve shut, before you connect it to the can. You would need to remember this at all times. The aluminum ones are much safer.
Woe is me: I cannot fit one of my remote canister winter stoves to these colored eBay adapters. The recess around the screw-thread is simple and narrow, sufficient for a commercial connector, but quite unlike the 1 in (2.54 cm) rim on a Lindal valve, which my connector relies upon. Have a look at the one above. What can I do?
I have two options. Make an adapter that goes from the screw-thread on the top of an eBay adapter to a Lindal valve rim, or modify one of these aluminum eBay adapters to look like a Lindal valve rim. I have done both.